Changes in magnesium and calcium in soils of the Broadbalk wheat experiment at Rothamsted from 1865 to 1966

Bolton, J.

doi:10.1017/s0021859600032184

Cited by 16 publications

(17 citation statements)

References 15 publications

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“…There was little change in pH over the last century in the Broadbalk soils, nearly all being in the 7–8 range, as would be expected for soils containing free CaCO 3 throughout the experimental period. The CaCO 3 content did, however, decrease with time, as generally observed in the Rothamsted field experiments (Bolton, 1977). Soil pH fell slightly with time in the unlimed Park Grass unfertilized soils and rose by about a unit in the limed unfertilized soils; it stayed just under 6 in the fertilized unlimed treatments.…”

Section: Resultssupporting

confidence: 75%

The turnover of organic carbon in subsoils. Part 1. Natural and bomb radiocarbon in soil profiles from the Rothamsted long‐term field experiments

Jenkinson

Poulton

Bryant

2008

European J Soil Science

111

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The Rothamsted long-term field experiments, started more than 150 years ago, provide unique material for the study of carbon turnover in subsoils. Total organic C, 14 C and 13 C were measured on soil profiles taken from these experiments, before and after the thermonuclear bomb tests of the mid-20th century. Four contrasting systems of land management were sampled: land cultivated every year for winter wheat; regenerating woodland on acid soil; regenerating woodland on calcareous soil; and old grassland. The mean radiocarbon ages of all the pre-bomb samples from cultivated land were 1210 years (0-23 cm), 2040 years (23-46 cm), 3610 years (46-69 cm) and 5520 years (69-92 cm). Bomb radiocarbon derived from thermonuclear tests was present throughout the profile in all the post-bomb samples, although below 23 cm the amounts were small and the pre-and post-bomb radiocarbon measurements were often not significantly different. Values of d 13 C increased down the profile, from À26.3& (0-23 cm layer, mean of all measurements) to À25.2& for the 69-92 cm layer. The C/N ratios decreased with depth in virtually all of the profiles sampled. Excluding the surface (0-23 cm) soils from the old grassland, the hyperbola m ¼ 152.1 À 2341/(1 þ 0.264n) gave a close fit to the radiocarbon data from all depths, all sampling times and all sites, where n is the organic C content of the soil, in t ha À1 , and m is the radiocarbon content of the soil, in D 14 C units, corrected for expansion or contraction of soil layers with time. The aberrant grassland soils almost certainly contained coal: one of them was shown by 13 C-NMR to contain 0.82% coal C. In Part 2 (this issue) of this pair of papers, these radiocarbon and total C measurements are used to develop and test a new model for the turnover of organic C in subsoils.

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Section: Resultssupporting

confidence: 75%

The turnover of organic carbon in subsoils. Part 1. Natural and bomb radiocarbon in soil profiles from the Rothamsted long‐term field experiments

Jenkinson

Poulton

Bryant

2008

European J Soil Science

111

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“…I t is probably caused by a relatively slow equilibration between limestone particles and the whole mass of surface soil at pH's above 7 when the rate of dissolution of limestone is less than at lower pH's (calcite has a minimum solubility at pH 8-3 at atmospheric partial pressures of CO 2 and at about pH 7-7 at average partial pressures of CO 2 in soils). In a previous paper (Bolton, 1972) a similar lack of equilibrium between free limestone and the whole soil mass in soils from the Broadbalk wheat experiment accounted for a relationship 1961196519701961Year 196519701974. Changes in soil pH from 1962 to 1974 at Rothamsted ( x ) and Woburn (O) a t i four rates of limestone application (0, 5 0 , 100, 20-0, Rothamsted; and 0, 4-6, 10-9, 17-3, Woburn; t CaCO/ha).…”

Section: Soil Phmentioning

confidence: 79%

“…It is well known that N ammonium acetate at pH 7 extracts not only Ca adsorbed on the exchange complex of soils but also Ca from any free limestone present, up to a limit of about 7000 mg Ca/kg under the extraction conditions used (Bolton, 1972). All of the Ca from undissolved added limestone in the soils would therefore be measured as 'exchangeable' Ca.…”

Section: 'Exchangeable' Calciummentioning

confidence: 99%

Changes in soil pH and exchangeable calcium in two liming experiments on contrasting soils over 12 years

Bolton

1977

J. Agric. Sci.

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SummarySoils were analysed from two long-term liming experiments on a sandy-clay loam at Rothamsted and a loamy sand at Woburn. Plots given four levels of limestone factorially combined with phosphate and potassium fertilizers (with magnesium subplots in 1974) were cropped with beans, barley, potatoes and oats from 1963 to 1974.The smallest limestone applications (5 t CaCO3/ha) increased soil pH the following year to values predicted by lime-requirement determinations using a standard advisory method. The larger limestone applications (10 and 20 t/ha) increased pH proportionally less. Soil pH decreased after the first year with 5 t/ha in both experiments but increased at the 20 t/ha rate for 6 years in the sandy-clay loam and for 3 years in the loamy sand before starting to decline.Exchangeable calcium (soluble in N ammonium acetate) decreased at approximately linear rates in all plots of both experiments from the first year. Slopes of the regressions were smaller at low than at higher rates of liming, depending primarily on the average pH. Rates of CaCO3 losses from the surface 23 cm of soil ranged from 225 to 823 kg/ha per year at Rothamsted and from 307 to 852 kg/ha per year at Woburn.Observed rates of Ca loss were compared with an empirical relationship suggested by Gasser (1973) between annual Ca losses and soil pH under average rainfall conditions and estimates based on a model system.

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“…Almost negligible losses from soils (e.g. Bolton, 1972;Rodgers, 1978) would contribute markedly to the increase of about 0.1 g m-* yr-' that has occurred in the deposition of nitrates over a similar period.…”

Section: Trendsmentioning

confidence: 97%

Long-term deposit at Rothamsted, southern England

Brimblecombe¹,

Pitman²

1980

Tellus

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Monthly rainfall analyses are available for Rothamsted and the surrounding area since 1853. Long records exist for NH,, NO, and CI, while SO, and pH measurements are less complete. The most striking change over the period is a shift in the seasonal distribution of the nitrate in the rain which has changed the deposit from <0.1 g m-2 yr-' in the m i d -1 9 w t u r y to -0.2 g m-2 yr-' at present. The pH, initially 4.7 in 1930, starts to decline only rec;Cntly by about 0.5 in the last 10-15 years. Chloride and ammonia show little change. Sulphate levels may have doubled since 1880 but there is no way to check their reliability.

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Changes in magnesium and calcium in soils of the Broadbalk wheat experiment at Rothamsted from 1865 to 1966

Cited by 16 publications

References 15 publications

The turnover of organic carbon in subsoils. Part 1. Natural and bomb radiocarbon in soil profiles from the Rothamsted long‐term field experiments

The turnover of organic carbon in subsoils. Part 1. Natural and bomb radiocarbon in soil profiles from the Rothamsted long‐term field experiments

Changes in soil pH and exchangeable calcium in two liming experiments on contrasting soils over 12 years

Long-term deposit at Rothamsted, southern England

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